Imatinib is the first of a new class of drugs that acts by specifically inhibiting a certain enzyme that is characteristic of a particular cancer cell, rather than non-specifically inhibiting and killing all rapidly dividing cells. Imatinib was a model for other targeted therapies that inhibited the class of enzymes, tyrosine kinases. Imatinib, present as its mesylate salt, multi-targets several pathways and is found to inhibit c-kit, PDGF-R and c-ABL. It is also known for its inhibition of T-cell proliferation stimulated by DCs and PHA. Imatinib Mesylate binds preferentially to ATP-binding sites of the c-kit proto-oncogene product, platelet-derived growth factor receptor (PDGF-R), and Abelson kinase (c-ABL) impeding the ensuing signal transduction. Imatinib, a reversible tyrosine kinase inhibitor, is effective in treatment of chronic myelogenous leukemia (CML), gastrointestinal stromal tumors, eosinophilic disorders, and systemic mast cell disease.
